Low frequency drone/vibration at 60ish mph

[Ultramaroon]

Originally Posted by Tcoat

@Ultramaroon ?


My tranny has always made a hum but after checking a bunch of test tones on YouTube it is probably more in the 150hz range.

I'm with @mrspindlelegs on this. Back when I was driving the Dolphin/Hilux, it had the same issue with the driveshaft support. It would resonate at a specific low frequency and would disappear. I don't think it's the bearing because I wouldn't expect it to make noise at a specific frequency. The isolator may be torn. The pillow block might be loose. The driveshaft may be damaged.

[LotsaMiles]

Originally Posted by Tcoat

Could you have an exhaust leak that you are thinking is vibrations?

No, I push in the clutch, put it in neutral, and the sound does not change. I even turn off the engine and the sound doesn't change. And it sounds the same whether in 5th or 6th gear. So it's almost certainly after the transmission.

[Tcoat]

Originally Posted by LotsaMiles

No, I push in the clutch, put it in neutral, and the sound does not change. I even turn off the engine and the sound doesn't change. And it sounds the same whether in 5th or 6th gear. So it's almost certainly after the transmission.

Had to ask. Everything seems to lead back to the support as Spindle and Ultra said.

[LotsaMiles]

Originally Posted by Ultramaroon

I'm with @mrspindlelegs on this. Back when I was driving the Dolphin/Hilux, it had the same issue with the driveshaft support. It would resonate at a specific low frequency and would disappear. I don't think it's the bearing because I wouldn't expect it to make noise at a specific frequency. The isolator may be torn. The pillow block might be loose. The driveshaft may be damaged.

I'm confused. I kinda see "driveshaft support" and "bearing" as the same thing. That is, the bearing is in the driveshaft support.


Are you suggesting the driveshaft support may simply be "loose" and just need the bolts tightened? I say this because I'm thinking it is always possible that they didn't fully tighten those bolts when they replaced my clutch (assuming they had to drop the driveshaft).

[LotsaMiles]

BTW, last time I did my own work on this stuff was my 1963 rambler classic. It had a fully enclosed driveshaft. I went through seven transmissions in that car, one of which I completely rebuilt myself. They were $35 each at the junkyard.

[Tcoat]

Originally Posted by LotsaMiles

BTW, last time I did my own work on this stuff was my 1963 rambler classic. It had a fully enclosed driveshaft. I went through seven transmissions in that car, one of which I completely rebuilt myself. They were $35 each at the junkyard.

Ya but $35 could have been almost a day's pay.
Someplace I have the invoice for changing the engine in my 64 Impala. I think it was about $135. Made for a pretty short cash month.

[Tcoat]

Originally Posted by LotsaMiles

I'm confused. I kinda see "driveshaft support" and "bearing" as the same thing. That is, the bearing is in the driveshaft support.


Are you suggesting the driveshaft support may simply be "loose" and just need the bolts tightened? I say this because I'm thinking it is always possible that they didn't fully tighten those bolts when they replaced my clutch (assuming they had to drop the driveshaft).

https://demos.starbase7.net/t3Portal...77870163885401


The rest of the manual is in Ultra's sig line.

[LotsaMiles]

Originally Posted by Tcoat

Ya but $35 could have been almost a day's pay.
Someplace I have the invoice for changing the engine in my 64 Impala. I think it was about $135. Made for a pretty short cash month.

I made $1.90 an hour at Shakeys. It was several days' pay.

[LotsaMiles]

Originally Posted by Tcoat

https://demos.starbase7.net/t3Portal...77870163885401


The rest of the manual is in Ultra's sig line.

Yeah, I saw that. I'm at work and that site is firewalled. I'll try when I gat home.


This does ease my mind quite a bit. A bad bearing can actually go a pretty long time compared to a bad U-joint. And it would be great if it was just some lose bolts.


I drove the box the 150 mile round trip today to be safe. Oddly, even with severe deer damage to the nose and 220k miles, I enjoy driving that thing as much as the FRS. Oddly, other drivers treat me differently, though.

[MuseChaser]

I have almost exactly the same symptoms in my '88 560SL..between 50 and 60mph, it produces what I can only describe as a"thrumming".... a deep vibration that pulses very slowly, about once a second or so, and sounds like the rumble track on a huge home subwoofer...more feel than sound and felt in the steering wheel too. Currently replacing the two flex couplers (this car's version of ujoints), the center support and bearing, and two shaft coupler bushings, and having the driveshaft rebalanced. Will report back.

[humfrz]

Originally Posted by LotsaMiles

BTW, last time I did my own work on this stuff was my 1963 rambler classic. It had a fully enclosed driveshaft. I went through seven transmissions in that car, one of which I completely rebuilt myself. They were $35 each at the junkyard.

Well, old timer, I suggest you take it into your local shop and ask them to check that bearing to see if it's tight. Yes, even it you costs you the back-in-the-day cost of a used transmission.


Maybe it's time for a new car -


humfrz

[Ultramaroon]

Originally Posted by LotsaMiles

I'm confused. I kinda see "driveshaft support" and "bearing" as the same thing. That is, the bearing is in the driveshaft support.


Are you suggesting the driveshaft support may simply be "loose" and just need the bolts tightened? I say this because I'm thinking it is always possible that they didn't fully tighten those bolts when they replaced my clutch (assuming they had to drop the driveshaft).

Well, it's a functional assembly. The pillow block is bolted to the chassis and the bearing floats inside a rubber doughnut. Here's that page of the manual.


https://demos.starbase7.net/t3Portal...01PKS00PX.html

[Ultramaroon]

Originally Posted by Tcoat

https://demos.starbase7.net/t3Portal...77870163885401


The rest of the manual is in Ultra's sig line.

Haha... Beat me to it. It's been a busy afternoon.

[LotsaMiles]

Originally Posted by humfrz

Well, old timer, I suggest you take it into your local shop and ask them to check that bearing to see if it's tight. Yes, even it you costs you the back-in-the-day cost of a used transmission.


Maybe it's time for a new car -


humfrz

I'm actually having a tough time with whether or not to keep it. I definitely get more respect from other drivers when I use it, and my driving style matches the car. It's worth about $8k now and I'm trying to decide whether to sell it while it's still worth something or just run it into the ground like I do with all my cars. I will never need to own another sports car. It's out of my system, finally. In fact, living in the sticks of KY, surrounded by spectacular twisties and back roads, I've actually considered getting something like a Slingshot or the last of the Ford Thunderbirds. That is, a convertible to simply cruise in with my wife. Maybe a '63 Lincoln convertible with suicide doors.


But I've replaced the clutch, the shocks, the spark plugs, the brakes, and a couple of wheel bearings and expect that stuff to all be good until 300k miles, so I just might keep it. I really hate getting rid of a car until it is facing major repairs that will cost more than the car is worth.


One thing's for sure, this thing is ten times the sports car my old '72 Opel GT was and 20 times the sports car my '72 Vega GT was. When I do sell it I'm gonna miss it. It is truly a special car, and fits my particular needs as though they asked me what I wanted before they built it. If I still lived in the Seattle area I would have had no need for it.